{"id":10307,"date":"2025-04-10T07:44:47","date_gmt":"2025-04-10T14:44:47","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=10307"},"modified":"2025-04-10T08:01:46","modified_gmt":"2025-04-10T15:01:46","slug":"leetcode-650-2-keys-keyboard","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/searching\/leetcode-650-2-keys-keyboard\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 650. 2 Keys Keyboard"},"content":{"rendered":"\n<p>\u8fd9\u9053\u9898\u76ee\u8fd8\u662f\u53ef\u4ee5\u7684\u3002\u6bcf\u4e2a\u9636\u6bb5\u6709\u4e24\u79cd\u9009\u62e9\uff0c\u6c42\u6700\u77ed\u7684\u51b3\u7b56\u6b21\u6570\u3002\u6709\u597d\u591a\u79cd\u4e0d\u540c\u7684\u505a\u6cd5\uff0c\u6211\u4eec\u4e00\u4e2a\u4e00\u4e2a\u6765\u3002<\/p>\n\n\n\n<p>\u65b9\u6cd51: BFS<br><br>\u628a\u95ee\u9898\u770b\u6210\u6c42\u65e0\u6743\u91cd\u56fe\u4e2d\u7684\u6700\u77ed\u8def\u5f84\uff0cBFS\u53ef\u4ee5\u627e\u5230\u6700\u4f18\u89e3\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u7684\u8282\u70b9\u6709\u4e24\u4e2a\u72b6\u6001\uff0c\u5f53\u524d\u7684\u957f\u5ea6\uff0c\u526a\u8d34\u677f\uff08\u4e0a\u6b21\u590d\u5236\u540e\uff09\u7684\u957f\u5ea6\u3002<br>\u957f\u5ea6\u8d85\u8fc7n\u4e00\u5b9a\u65e0\u89e3\uff0c\u6240\u4ee5\u6211\u4eec\u7684\u72b6\u6001\u6700\u591a\u53ea\u6709n<sup>2<\/sup>\u79cd\uff0c\u6bcf\u4e2a\u72b6\u6001\u6700\u591a\u62d3\u5c552\u4e2a\u65b0\u7684\u8282\u70b9\u3002<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2025\/04\/2-keys.png\"><img loading=\"lazy\" decoding=\"async\" width=\"960\" height=\"540\" src=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2025\/04\/2-keys.png\" alt=\"\" class=\"wp-image-10312\" srcset=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2025\/04\/2-keys.png 960w, https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2025\/04\/2-keys-300x169.png 300w, https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2025\/04\/2-keys-768x432.png 768w\" sizes=\"auto, (max-width: 960px) 100vw, 960px\" \/><\/a><\/figure>\n\n\n\n<p>\u65f6\u95f4\u590d\u6742\u5ea6\uff1aO(n<sup>2<\/sup>)<br>\u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(n<sup>2<\/sup>)<\/p>\n\n\n\n<pre lang=\"c++\">\nclass Solution {\npublic:\n  int minSteps(int n) {\n    vector<vector<bool>> seen(n + 1, vector<bool>(n + 1));\n    queue<pair<int, int>> q;\n\n    auto expand = [&](int len, int clip) {\n      if (len > n || len > n || seen[len][clip]) return;\n      q.emplace(len, clip);\n      seen[len][clip] = true;\n    };\n\n    int steps = 0;\n    expand(1, 0); \/\/ init state.\n    while (!q.empty()) {\n      int size = q.size();\n      while (size--) {\n        auto [len, clip] = q.front(); q.pop();\n        if (len == n) return steps;\n        expand(len, len); \/\/ copy.\n        expand(len + clip, clip); \/\/ paste.\n      }\n      ++steps;\n    }\n    return -1;\n  }\n};\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u8fd9\u9053\u9898\u76ee\u8fd8\u662f\u53ef\u4ee5\u7684\u3002\u6bcf\u4e2a\u9636\u6bb5\u6709\u4e24\u79cd\u9009\u62e9\uff0c\u6c42\u6700\u77ed\u7684\u51b3\u7b56\u6b21\u6570\u3002\u6709\u597d\u591a\u79cd\u4e0d\u540c\u7684\u505a\u6cd5\uff0c\u6211\u4eec\u4e00\u4e2a\u4e00\u4e2a\u6765\u3002 \u65b9\u6cd51: BFS \u628a\u95ee\u9898\u770b\u6210\u6c42\u65e0\u6743\u91cd\u56fe\u4e2d\u7684\u6700\u77ed\u8def\u5f84\uff0cBFS\u53ef\u4ee5\u627e\u5230\u6700\u4f18\u89e3\u3002 \u6211\u4eec\u7684\u8282\u70b9\u6709\u4e24\u4e2a\u72b6\u6001\uff0c\u5f53\u524d\u7684\u957f\u5ea6\uff0c\u526a\u8d34\u677f\uff08\u4e0a\u6b21\u590d\u5236\u540e\uff09\u7684\u957f\u5ea6\u3002\u957f\u5ea6\u8d85\u8fc7n\u4e00\u5b9a\u65e0\u89e3\uff0c\u6240\u4ee5\u6211\u4eec\u7684\u72b6\u6001\u6700\u591a\u53ea\u6709n2\u79cd\uff0c\u6bcf\u4e2a\u72b6\u6001\u6700\u591a\u62d3\u5c552\u4e2a\u65b0\u7684\u8282\u70b9\u3002 \u65f6\u95f4\u590d\u6742\u5ea6\uff1aO(n2)\u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(n2) class Solution { public: int minSteps(int n) { vector seen(n + 1, vector(n + 1)); queue q; auto expand&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[44],"tags":[34,18,42],"class_list":["post-10307","post","type-post","status-publish","format-standard","hentry","category-searching","tag-bfs","tag-dp","tag-search","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10307","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/comments?post=10307"}],"version-history":[{"count":5,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10307\/revisions"}],"predecessor-version":[{"id":10314,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10307\/revisions\/10314"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=10307"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=10307"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=10307"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}